Safety drill pipe for oil well drilling



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United States Patent O SAFETY DRILL PIPE'FOR OIL WELL DRILLING Warner A. Williams, Miami, Fla.

Application February 5, 1954, Serial No. 408,466

3 Claims. (Cl. 255--28) The invention relates to a well drilling pipe comprised of a string of pipe sections connected together for deep well drilling, wherein auxiliary sections are employed to assure recovery of the complete continuous string in event a break should occur in one or more sections of the primary drill pipe.

An important object of the invention is to provide a string of auxiliary connector sections within the primary drill pipe sections, which auxiliary sections are arranged for individual rotation relative to each other or relative to the section of drill pipe in which each is housed.

Another object of the invention is to provide a deep well drilling device formed of sections connected together to form a continuous string, wherein auxiliary connector sections are housed within the primary pipe sections so as to be individually rotatable, whereupon when a break occurs in one of the primary pipe sections, the upper sections of the string will immediately rotate freely and the operator will know immediately that a break has occurred. The sections beneath the break remain secured to the upper sections and can be withdrawn from the well for repair or replacement of the broken section.

A further object of the invention is to provide spring means for cushioning the shock of separation when a break occurs in one of the primary pipe sections.

Other objects and advantages will be apparent upon examination of the following specification and appended drawing in which:

Fig. 1 is a sectional View through one of the drill string sections with portions of the comparable preceding and succeeding sections shown; and

Fig. 2 is a sectional view similar to Fig. 1 showing the approximate position of the relative parts after a break has occurred in one of the primary pipe sections.

In a deep well drilling pipe string wherein the length of 4the string is made up of a multiplicity of pipe sections removably connected together, any break in one of the pipe sections during the drilling operation would normally cause all of those sections beneath the broken section to become lost in the Well. It has been known that by using auxiliary sections whenever a break occurred in one of the primary pipe sections, the sections beneath the break could be saved and withdrawn from the well for re-use. The invention contemplates an improved construction of combined primary and auxiliary sections which make up the complete drill string.

The drill pipe may be made up of the primary outer pipe section generally referred to by the numeral 2 and the auxiliary inner pipe section generally referred to by the numeral 3 and the preceding and succeeding inner and outer pipe sections may be of like construction, whereby a drill string of any desired length may be obtained.

The outer section has a central shank portion 4, a head portion 5 and a tail portion 6. The head portion may be externally threaded at 7 for threaded engagement with the internally threaded tail portion of the preceding section. Each outer section is provided with a concentric 2,768,812 Patented Oct. 30, 1956 rice bore 8 extending throughout the full length thereof an a counterbore 9 in the tail portion.l

Each outer section has received therein an auxiliary inner section which is comprised of a tubular shank 10 which is rotatable within bore 8 and which is capable of axially directed rectilinear movement within bore 8, such as when a break occurs. The inner section has at one end a radially projected annular flange 11 which is concentrically received within the counterbore 9 and at its opposite end a head 12 which affords an annular shoulder 13 which abuts the annular end face 14 of the head portion of the outer section. A compression spring 15 is encircled on the shank 10 withinthe counterbore and abuts the annular shoulder 17 formed at the base of the counterbore and normally exerts tension against an axial thrust bearing 18 which i'n turn abuts the annular shoulder formed at the base of the annular flange 11. The end face of the inner section at its flange end is provided with a generally concave surface 19 which corresponds with the convex `end face 20 on the head 12 and provides in effect a partial ball and socket joint which permits each inner section 3 to be independently rotatable within the outer section relative to its preceding and succeeding inner sections, the reason for which will be set forth hereinafter.

In the assembly of each complete section the inner section 3 can be inserted through bore 8 from the head end of the outer section and then the compression spring can be placed over the inner section and inserted into the counterbore and a swagingoperation performed at the flange end of the inner section to form the annular ange 11.

When a break as indicated by the numeral 22 occurs in the outer section during the drilling operation, the lower portion thereof is suspended relative to the upper portion as a result of the head 12 of the inner section abutting against the end face 14 of the outer section. The upper end of the inner section, through flange 11, is anchored within the counterbore of the Iupper portion of the outer section causing compression of the spring, thereby causing the flange end of the inner section to separate from the head of the adjacent succeeding inner section. There may be a large number of sections beneath the broken one and the total weight of same would determine the amount of compressive force imposed on the spring. At the moment the break occurs, the spring serves to cushion the shock resulting from the break. Also at the moment the break occurs the load which was being imposed on the entire string of sections, as a result of the drilling operation being consummated at the lowermost section, is promptly relieved and those sections above the broken section continue to rotate under no load conditions until the operator turns off the power unit. The auxiliary inner sections, as previously mentioned herein, are independently rotatable relative to each other and consequently the string of inner sections beneath the broken outer section will tend to cease rotating when the break occurs.

After turning off the power unit the operator can then retrieve the entire string of inner and outer sections from the well for repair or replacement of the broken outer section and no part of the drill string is lost in the well.

I claim:

l. A well drilling pipe comprising a plurality of hollow sections, each section being internally threaded at one end and externally threaded at its opposite end, whereby each section is threadedly connected to each succeeding section; a rod slidably and rotatably received in the interior Iof each section; each section having a counterbore at one of its ends; a compression spring received in each counterbore; each rod having a radially projecting ange against which the spring abuts; a shoulder at the base of each counterbore against which the opposite end of the spring abuts;l a head on one end of each rod and abutting the end of the section for limiting axial movement in one direction of the rod relative to its associated section; the head end of each rod normally abutting the opposite end of the succeeding rod.

2. A well drilling pipe as set forth in claim 1 wherein the head end of each rod has a convex surface and the opposite end of each rod has a concave surface corresponding to the convex surface of each preceding rod.

3. A well drilling pipe comprising a; plurality of *sections removably connected together to form a continuous string of sections, each section having a bore therethrough and a counterbore extending partially therethrough, said counterbore opening into one end of each section; a rod rotatably mounted within the bore of each sectionY and being capable of limited axial movement within the section; a shank portion on each rod; a head having a convex end surface at one end of each shank portion; a flange having a concave end surface at the opposite end of each shank portion, said convex end surface of each rod being normally frictionally engaged by the concave end surface of the preceding rod ilange, said ange and head of each rod being of larger diameter than the shank portion of said rod; each ange being positioned Within each counterbore of each section; the head of each rod abutting the end of its associated section for preventing axial movement of the section in one direction; a compression spring on the shank portion of each rod and within the counterbore of each section; each spring abutting the ange of each rod; a shoulder at the base of each counterbore and each spring abutting the shoulder of each section.

References Cited in the tile of this patent UNITED STATES PATENTS Soderstrom Jan. 30, 1912 

